Gyroscopic Payload Motion Control for Floating Installation of Offshore Wind Turbine Towers

Abstract

This thesis explores the potential of gyrostabilizers in mitigating payload motion during the installation of offshore wind turbine towers from floating platforms. It introduces Sway Damping Gyroscopes (SDG) as an actuator, utilizing gyroscopic precession for stabilization, positioned below the crane hook. The study develops a two-dimensional Linear Time-Invariant (LTI) model and controller design to address system dynamics complexities, particularly in managing sharp phase shifts and resonance modes. Controller design involves loop shaping to achieve stability for a wide range of tower lengths, with stability verified using the Nyquist stability criterion. The closed-loop system analysis demonstrates effective dampening of resonance modes in responses to wave disturbances, and slight reductions in response levels to wind disturbances. Historical workability analysis reveals an increase in workability with SDG implementation, alongside significant power demands and a nonlinear relationship between peak power and workability. Sensitivity analysis underscores the impact of tower length variations on controller performance, emphasizing careful controller and sling length selection for reliable installations. The SDG system consistently provides higher workability compared to the original system throughout system parameters variations, highlighting its potential for enhancing floating wind turbine tower installations. Further research is recommended to validate these findings under realistic power demand conditions and confirm the validity of model simplifications.